Apparatus for formation sampling



A. L. SMITH APPARATUS FOR FORMATION SAMPLING Oct. 7, 1958 2 Sheets-Sheet 1 Filed May 2, 1955 INVENTOR. By 7%@ /4/0/720 Jm/z// L4M ff/ ATTORNEY;

Oct. 7, 1958 A. L. SMITH 2,855,050

APPARATUS FOR FORMATION SAMPLING Filed May 2, 1955 2 Sheets-Sheet 2 INVENTOR.v

BY OMM KwQ/,

2,855,050 APPARATUS FOR FRMATION SAMPLING Alonzo L. Smith, Houston, Tex.

Application May 2, 1955, Serial No. 505,234

4 Claims. (Cl. 166-103) This invention relates to the new and useful improvements in methods and apparatus for formation sampling.

In the drilling of oil and gas wells, it is often desirable to obtain information as to the nature of the well formations through which the bit is drilling. The common practice is to obtain and test well cores from such formations to determine whether oil and/ or gas is present in the formation. The obtaining of well cores is expensive, particularly if a conventional drilling bit is being used at the time, because in such case, it is necessary to withdraw the complete string of drill pipe from the well hole and change the drill bit to a corng bit in order to obtain the core. The use of a con'ng bit continuously in place of the usual drill bit is also impractical and very expensive, primarily because drilling with coring bits is considerably slower than drilling with drill bits and very little of the core obtained is of any value since most of the drilling occurs through areas where oil and gas are not present.

Therefore, it is an object of this invention to eliminate unnecessary coring costs and to minimize the taking of cores for determining the presence of oil and/ or gas in a well formation.

An important object of this invention is to provide an improved method and apparatus for obtaining a sample of the well uid in the vicinity of the drill bit while a conventional drill bit is in the well hole whereby tests of such uid can be made to determine whether oil or gas, or both, are present in the formation being drilled by the drill bit.

l Another object of this invention is to provide an improved method and apparatus, wherein the drilling mud or fluid adjacent the wellformation being drilled with a conventional drill bit is sampled to determine whether oil or gas is present in the formation by causing the drilling lluid adjacent the formation to rise through the slush passages in the drill bit to a formation sampling apparatus disposed in the drill pipe above the drill bit.

A further object of this invention is to provide an -improved apparatus for obtaining samples of well fluid to determine whether oil and/or gas is present in the formation being drilled, which apparatus is adapted to be lowered into conventional drill pipe for positioning above a conventional drill bit, the apparatus beingso constructed that it is capable of trapping a sample of the well uid received through the slush passages in the drill bit from adjacent the formation being drilled.

A still further object of this invention is to provide an improved apparatus for obtaining samples of well fluid while the drill bit is in the well bore, wherein such apparatus includes a valve means which is adapted to be closed during the retrieving of a fluid sample from the well but which is so constructed'that mud or other fluid can be pumped downwardly through the drill pipe and said apparatus to prevent a blowout of the well while said apparatus is in the drill pipe.

The construction designed to carry out the invention States Patent O assess@ Patented Octf 7" will be hereinafter described, together with other features thereof.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown and where- Figure 1 is a view, partly in elevation and partly in section, illustrating the apparatus of this invention in po-. sition for carrying out the method of this invention.

Figure 2 is a view, partly in elevation and partly in section, illustrating the details of the apparatus of this invention. l

Figure 3 is a horizontal sectional view taken on line 3--3 of Figure 2.

Figure 4 is a view, partly in section and partly in Yelevation, of a modification of the sampler apparatus ill'ustrated in Figure 2.

Figure 5 is a view, partly in elevation and partly in section, illustrating another modification of the apparatus of Figure 2.

In the drawings, the letter A designates generally the, formation sampling or testing apparatus of this invention which is adapted to be disposed in the lower end of a section of drill pipe P having a drill bit B attached or secured to the lower end thereof. The drill bit B is illus-` trated in the drawings as being of the lishtail or drag blade type, but other types of drill bits could be utilized for the drilling of the well bore or hole W so long as the drill bit has one or more slush or mud passages 10 and lll (Figure 1). The drill bit B thus has conventional slush passages 10 and 1l through which mud or slush is pumped downwardly from the drill'pipe P into the annulus 12 between the drill pipe P and the wall of the well bore W during the drilling of the well bore W.

The sampling apparatus A of this inventionl is adapted to be used by positioning same in the lower end of the drill pipe P with such apparatus being seated upon the upper end of the drill bit B, or being otherwise disposed in the drill pipe P in iiuid communication with the slush passages 10 and 11 of the bit B. Such apparatus A includes a container or barrel 15 which is preferably substantially cylindrical in construction and which has an open lower end l5a and an open upper end lSb. The lower annular edge 15C of the barrel l5 has an annular sealing ring 20 formed of rubber, felt, orl the like, secured thereto by screws 21 or any equivalent fastening means. The diameter of the opening 15a and the width of the sealing ring 20 are such that when the apparatus A is positioned in the drill pipe P of the drill bit B (Figure l), the open upper ends of the slush passages i0 and ll are disposed within the contines of the sealing ring 20 and are therefore in fluid communication with the passage 15a with ilow around the exterior of the barrel l5 fromthe passages 10 and 11 being prevented or at least minimized so that the 4majority of iiuid flows from the passages l0 and 11 into the interior of the barrel l5.

An annular valve seat 22 having external threads 22a is threaded within the bore of the barrel 15 in engagement with the internal threads 15d, although it will be appreci ated that such valve seat 22 could be secured in position by welding or other equivalent securing means. A longitudinal central passage 22b is provided through the valve seat 22 and an arcuate recess 22e is formed at the lower portion of the seat 22 to provide the seating surface thereof. The seating surface 22e is of such curvature that the external surface of the ball or Valve 25 is adapted to engage therewith in sealing contact for closing fluid ow through the central passage 22b. The valve 25 is attached vto a valve stem orrod 26 which extendsupwardly therefrom and which has at its upper end a fishing neck 27 which is preferably conical and which is adapted to be pulled upwardly by the usual type of well grapple (not shown) which engages below the annular lateral surface 27a in the known manner.

An annular guide bushing 30 is centrally positioned within the bore of the barrel 15 and is secured to support ribs 31 which extend to, and are connected with, the internal surface of the barrel 15 by welding or any other suitable type of connection. Such annular guide bushing 30 guides the movement of the valve stem 26 as it moves longitudinally relative to the barrel 15. The upward limit of the movement of the valve member 25 is determined bythe contact of the valve member 25 with the seating surface 22e of the valve seat 22. The downward movement of the stem 26 and the'valve member 25 is limited by the contact of a stop pin 35 on the stem 26 with the upper end of the annular bushing 30. Such stop pin 3S also holds the fishing neck 27 above the upper end of the barrel 15 a sufficient distance so that the lower lateral surface 27a thereof is exposed adequately for engagement with the well grapple (not shown).

In carrying out the method of this invention, the usual well pump (not shown) which is located at the surface of the well W and which normally pumps drilling mud or slush downwardly through the interior of the drill pipe P and outwardly through slush passages l and 11 into the annulus 12 of the well bore W, is stopped and is disconnected from the drill pipe. By thus stopping the ow of the drilling mud or slush, the height of the mud inside the drill pipe P and in the annulus 12 of the well bore W become level with each other since both columns of mud are interconnected through the passages 10 and 11 in the bit B and also since the mud columns in the pipe P and in the annulus 12`are under atmospheric pressure. Formation cuttings and well fluids such as oil and gas are held in suspension in the mud or slush when the pump actionl is stopped, due to the viscosity and gel strength of the mud commonly employed for drilling.

Prior to the lowering of the apparatus A into the drill pipe P, such pipe P and bit B are raised to permit dis- Y' connection of the conventional kelly or square drive at the surface of the well so as to open the upper end of the drill pipe P for inserting the apparatus A thereinto. Then, with the bit B off the bottom of the well bore W several feet or more, the apparatus A is dropped down the pipe P and stops upon contact with the upper end of the drill bit B. Thereafter, the bit B and the apparatus A are lowered together on the pipe P to the bottom of the well bore W, and during such lowering, the mud at the lower end of the bore W is forced upwardly through passages 10 and 11 into the interior of the apparatus A, whereupon the apparatus A with the fluid sample therein is retrieved from the pipe P by the engagement of the fishing neck 27 with a conventional well grapple, as is more fully explained below in connection with the preferred alternate procedure.

If, instead of lowering the apparatus A into the pipe P while the bit B is off the bottom, the pipe P is lowered to thebottom and thereafter the apparatus A is dropped into the pipe P, then, the following preferred alternate procedure is employed.

After the mud levels inside and outside of the drill pipe P have become equal or level, the sample apparatus A is dropped into the drill pipe P and it falls by gravity to the bottom of the drill pipe P and stops upon contact with the'upper end of the drill bit B (Figure 1). The drill pipe P is then rotated a few revolutions or at least a sufficient number of revolutions so that a portion of the wellformation W is cut by the drill bit B; since the pump supplying` the drilling mud is stopped, the cuttings and. oil andfgas which are released from Vthe formation as a result of the rotatingstep remain in thedrilling mud, in the vicinity of thedrill bit B.

To obtain a sample of such drilling mud adjacent the bit B to determine whether oil or gas is present in the formation then being drilled, some of the mud from the inside of the drill pipe P is bailed or is otherwise withdrawn therefrom at the surface of the well so as to lower the level of the mud in the drill pipe P. As the level of the mud in the drill pipe P is lowered, the level of the mud in the annulus 12 drops due to the fact that the uid in the drill pipe P and in the annulus 12 are in communication and tend to seek to the same level. Therefore, the amount cf mud removed from the drill pipe P will determine how much the level of the mud will drop in the annulus 12 and, as the level of the mud in the annulus drops, mud in the vicinity of the drill bit B is caused to rise through the slush passages and 11 into the bore of the barrel 15. The cuttings and oil and gas in the mud which have been released by the drilling step previously described are thus carried upwardly into the barrel of the sampling apparatus A. The valve is maintained in an open position (Figure 2) by its own weight so that the mud with the cuttings and the oil and/or gas is carried upwardly around the valve member 25 and through the central bore 22b of the valve seat 22 into the barrel 15 above the valve seat 22.

When a sufficient quantity of the mud has been removed from the upper end of the drill pipe P in order to obtain a desired amount of the well fluid from the vicinity of the drill bit B within the sampling apparatus A, then a well grapple (not shown) of conventional construction is lowered into the drill pipe P and is attached to the fishing neck 27 so that upon raising of the grapple in the drill pipe P, the stem 26 is first raised with the valve 25 to close the central bore 22b of the valve seat 22 by seating the valve 25 on the seating surface 22C. Continued raising of the grapple results in an upward movement of the entire sampling apparatus A and thereby results in a lifting of the sample of the fluid trapped therein.

After the apparatus A is removed from the drill pipe P at the upper end'of the well bore 1V, the contents of the apparatus A are then released and examined so that the operator can determine whether coring operations are desirable or whether other formation testing tools for the potential of oil and gas should be employed.

Although the above described method has been set forth as including the step of rotating the pipe after the disconnecting of the mud pump, it should be understood that in some cases the sample may -be taken into the apparatus A without such rotation of the drill bit. Also, it may be desirable in some instances to cause the drilling mud in the annulus 12 to flow upwardly into the apparatus A by the application of a suction pump to the drill pipe rather than by the hailing of the mud from the drill pipe, or by adding mud outside the drill pipe to cause mud to flow through the passages in the bit to the apparatus A; however, such methods of obtaining the sample in the apparatus A are not as simple and as f positive as the bailing method.

lt should also be pointed out that the desired sample can be obtained in the lower end of the drill pipe P prior to the lowering of the sampling apparatus A into the drill pipe P. In other words, the well pump could be disconnected from the drill pipe and the mud could be hailed or withdrawn` from the drill pipe in order to draw or move the sample of mud in the vicinity of the drill bit into the lower end `of the drill pipe and thereafter the apparatus A could be dropped into the well pipe P so that it would then immediately be filled with the sample as it reached the lower end of the drill pipe P.

It will be evident that while the apparatus A of this invention is in the drill pipe P, the valve 25 is in its lowered or open position so that if excessive gas pressure should develop in the well during the foregoing procedures, mud or other tiuid can be pumped downwardly through the apparatus A so as to prevent a blowout of the well. The mud or fluid is preferably supplied to the drill pipe P at the surface of the well from the usual mud pumps (not shown).

In Figure 4, a modification of the apparatus A of Figure 2 is illustrated, wherein the modified apparatus A-ll has means therewith for opening a check valve C positioned above the bit B, The check valve C is of conventional construction and one type thereof is shown for illustrating the operation of the apparatus A-1 of Figure 4. The parts of the apparatus A-l which are identical with the apparatus A have the same numerals. The apparatus A-l has an actuating member or probe 4G preferably in the form of a ball which is connected to, and depends from, the ball valve 25 by an extension or support rod 41. The probe 4@ is of small enough size to pass through the opening 43 above the check valve 44 so as to urge the valve 44 downwardly against the action of the spring 45 to permit uid flow upwardly around said valve 44 and through said opening 43 t-o the interior of the barrel l5. The weight of the valve 2.5, probe 40 and the other parts connected therewith must, of course, be sutiicient to overcome the upward urging of the spring 45 on the valve 44.

The apparatus A-l is also different from the apparatus A in that the shing neck. 27 is eliminated and instead, a wire line 47 or other llexible support is connected to the hook or eye 43 at the upper end of the rod 26, whereby the apparatus A-l may be retrieved by raising upwardly on line 47 and without requiring a shing or grappling tool. Of course, it will be appreciated that the wire line V can be also used with the apparatus A instead of the fishing neclr 27, and similarly the shing neck 27 can be used in the apparatus A-ll instead of the wire line 47.

The operation of the apparatus A-l in carrying out the method of this invention would be the same as explained above in connection with the apparatus A, except that the probe ill would open check valve C upon the seating of the apparatus Awll on the upper end of the check valve. Also, the apparatus A-l is lowered and retrieved on the wire line 47.

Another modification of the apparatus A of Figure 2 is illustrated in Figure 5 wherein the apparatus A-Z is illustrated as being identical with the apparatus A except that an actuating member or probe 54B is mounted on an extension rod 5l which is connected to the lower portion of the container or barrel by a frame having strips 52 and ring 53 which is threaded or otherwise connected to the threads 15d in the barrel 15. Such construction represents only one embodiment wherein the probe 50 is connected to the lower end of the container or barrel 15 and it will be appreciated that the manner of making such connection can be varied by those skilled in the art.

The operation of the apparatus A-2 in carrying out the methods of this invention is the same as described above in connection with the apparatus A except that the probe 50 operates the check valve 44 to `open same when the apparatus A-Z seats on the upper end of the valve C. Either the fishing neck 27 or the wire line 47 may be used with the apparatus A-2.

It will be understood that the invention is not limited to the use of the particular valve construction illustrated since any type of valve may be used which will open for upward fluid iiow into the barrel 15 but which will remain closed after a sample of fluid is trapped in the barrel 15. For example, the well-known apper type of valve made of rubber or other flexible material or the conventional stopcock valve could he employed as such valves would open on upward ow but would prevent downward flow.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and material, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, Without departing from the spirit of the invention.

What is claimed is:

l. In combination with a drill bit having slush passages extending downwardly from the upper end thereof for discharging drilling mud downwardly into a well bore from a pipe supporting the bit and a downwardly opening check valve in said pipe above said bit, an apparatus adapted to obtain a sample of the drilling mud in the vicinity of the drill bit including, a container means for confining the sample, means for establishing uid communication between the container means and the slush passages in the drill bit whereby iluid can tlow from the well bore in the vicinity of the drill bit through the slush passages to said container means, an upwardly closing valve at the lower end of the container adapted to be opened when the container is in position establishing communication between the container and slush passages and adapted to be closed when the container is moved upwardly within the well bore, and means on said apparatus `for opening said check valve to permit the fluid ow to the apparatus from the slush passages.

2. The structure set forth in claim 1, including a seal means on the lower end of said container means spaced inwardly and out of contact with said pipe for preventing fluid ilow between the exterior and the interior of said container means.

3. The structure set forth in claim 1, wherein said means on said apparatus for opening said cheek valve includes an actuating member mounted on the lower end of said container means and extending downwardly therefrom for holding said check valve open for fluid flow therethrough to said container means.

4. The structure set forth in claim 1, including a connection means connecting said means for opening said check valve to said downwardly opening valve.

References Cited in the le of this patent UNITED STATES PATENTS 492,117 Smith Feb. 21, 1893 1,247,092 Dodds NOV. 20, 1917 2,161,282 Crowell June 6, 1939 

